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E46 (1999 - 2006) The fourth generation 3 Series (E46 chassis) was introduced in 1999 and set the standard for engineering and performance during it's years of production including being named to Car & Driver's 10 best list every one of those years! ! -- View the E46 Wiki

Hi, I have a 2000 E46 328 with auto A/C and unusual problem. During cold weather where the temperature set on the control panel causes the vents to blow warm/hot air, it blows very hot as soon as heat is available after start-up. this continues relentlessly for about 20 minutes and the air inside the car becomes too hot for comfort - even with the controls set to 20C. After 20 minutes all heat ceases and the fan blows totaly cold air from then on. The wheel control on the dash is set to one or two red dots (after the 20 minute cut-off these have no effect). The fan functions perfectly and responds to all control settings. It seems that heat is present in the heater matrix because after the 20 minute cut-off the defrost button will still blow hot air to the screen vents! Can anyone help?

Hi, I have a 2000 E46 328 with auto A/C and unusual problem. During cold weather where the temperature set on the control panel causes the vents to blow warm/hot air, it blows very hot as soon as heat is available after start-up. this continues relentlessly for about 20 minutes and the air inside the car becomes too hot for comfort - even with the controls set to 20C. After 20 minutes all heat ceases and the fan blows totaly cold air from then on. The wheel control on the dash is set to one or two red dots (after the 20 minute cut-off these have no effect). The fan functions perfectly and responds to all control settings. It seems that heat is present in the heater matrix because after the 20 minute cut-off the defrost button will still blow hot air to the screen vents! Can anyone help?

Weird. Couple things to try, 1. Use a vacuum and suck out the crap/dust that accumulates on the two vents on either side of the climate control panel. I think one of them is a sensor for the "auto" function. 2. Is your thermostat operating properly? If it is getting stuck closed this could explain the lack of heat. 3. Try replacing your FSU (final stage unit) and see if that helps. 4. Your climate control might be faulty, you could replace that too

Hope that helps. I just recently had NO heat and it was my thermostat going bad (finally failed and left me on the side of the road)

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So I have a similar, yet different problem. Hear me out here, and please help!!!

I have a 2000 BMW 323ci with about 90K on it. I was driving the car normally at 60-70 km/hr for about 20 mins and happened to look at the temperature gauge and the needle was way over on the right at the end of the red zone (see pic below). There was no heat coming from the vents, and the interior of the car was ice cold. I wasn't revving the engine or doing anything out of the ordinary except driving in the city. I drove for another 5-10 mins to get home and shut the car off. Mind you the weather here in Canada is at -20C (-4F)...

The next day I brought it to a local mechanic who said that the problem was a busted thermostat that was stuck closed. So after $280, he apparently replaced the thermostat and changed the coolant, and then sent me off.

The next day, I started the car and let it warm up for about 3 mins or so before driving, and within 10 mins the same thing happened again - needle goes straight to the red zone and stays there. No hot air coming in from the vents. I pull over immediately, shut the engine off, let it cool down for 5 mins. And then started it again, this time letting it idle for 8-10 mins before driving off. Then I proceeded to drive for 30 mins, and everything returned back to normal. Needle was a little past the blue/cold range the entire time, and there was hot air coming in (interior temperature is set to 23C (73F).

I decided to bring it into Europa Motors to get a second opinion (accredited independent BMW service providers). The mechanic said he couldn't find any problems except maybe the thermostat signal/computer had to be reset, but noticed it was strange that the coolant was white coloured.

So off I go again into the car, warming it up for 3 mins before driving off. Then within a few minutes, the same problem re-appears. Needle goes to red zone. I turn around and bring it back to shop to show them, and all of them are scratching their heads. Now the car is in their shop until Monday before they can do a more detailed diagnosis.

I know, I know... But it's weird cuz the needle goes straight from blue to red. It doesn't slowly creep up. I was only a block away from the shop, so I figured I'll just turn it around and drive it back immediately.

I find the windscreen demister on the 3 series quite weak. I would say that the heating system is not one of the cars strong points. If the blower is on a high setting and windscreen only is selected, some air comes through my vents. It's as if there is too much air being forced through the system and the vents are a safety valve!

Hello guys,
I arrived to this forum through a Google search...
I have a problem similar to Steve328's. I will certainly try and vacuum the vents, but my problem does not affect the AUTO function, so perhaps the solutions is different too...
Well, from my 318Ci air, all of a sudden (till yesterday the climate control was GREAT!), is too hot. However, this is not just a problem with AUTO. It is too hot even if I set the fan to minimum, manually.
Out of curiosity, anybody knows where, in my car, is the thermometer?
Thanks!
Marco

He said thermometer, not thermoSTAT. The thermometer is behind that vent to the left (on american cars) of the temp setting on your climate control. You can adjust the "hotness" of the air coming out by rolling the dial between your two middle dash vents to less red dots or even the blue ones.

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Good!
It seems that vacuuming the vents (where the thermometer is, but - just to be sure :-) - the air vents too) solved my problem and the temperature is again well controlled.
Thanks for the hints!
I must say that I was scared: the air was so hot that I could smell something like burnt. Yet just some vacuuming did the job...

Hello. I know this is an old thread, but it seems to apply to the issue I am having.

I have a 2000 328i. The heat on it does not work. Or, does not work most of the time i should say. I can turn it on and the blower works, but no heat. However, on two occasions, it did work. And sometimes, when the heat is not working, I can turn of the windshield defrost, and hot air will come out.

I see where smolck suggested vacuuming out the vent by the climate control panel. I thought I would try this, but I am not sure where this is located. Can someone give me some details?

Hello. I know this is an old thread, but it seems to apply to the issue I am having.

I have a 2000 328i. The heat on it does not work. Or, does not work most of the time i should say. I can turn it on and the blower works, but no heat. However, on two occasions, it did work. And sometimes, when the heat is not working, I can turn of the windshield defrost, and hot air will come out.

I see where smolck suggested vacuuming out the vent by the climate control panel. I thought I would try this, but I am not sure where this is located. Can someone give me some details?

Thanks

Just to the left of the temp readout display you have a small set of vents. However, in your case it sounds more like you are low on coolant which will cause you not to have heat. I would bleed your system and top it off and see if that fixes the problem.

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Let me just mention im an experienced mechanic, but never looked a BMW before, so its all new to me. I just got the car a couple months ago.

I checked the coolant level via the container cap near the radiator that said "do not open hot" The float indicator appeared to show it to be right at the full mark. This is with the car cold. If that offers any insight regarding the coolant...

And I tried to locate the vents but i still dont see them. By temp readout display, do you mean the gauge in the cluster?

You can adjust the "hotness" of the air coming out by rolling the dial between your two middle dash vents to less red dots or even the blue ones.

LOL... Maybe I should have read this a little closer before i posted. Anyway, I found the dial, and sure enough, it was turned all they way to cold. I turned it to hot and it seems to be working. Thanks smolck.

I'm jumping in as my fan motor has stopped also. I put a new FSR in 3 weeks ago. That did not fix. I then R&R the fan motor and did some serious cleaning on the brushes. Put it back together and it worked three weeks. Now, no blower again. I'm thinking it has to be the blower motor. Could there be any other culprit??